Recently, as an image forming apparatus that forms an image on a recording medium, there is an apparatus that thermally decolorizes an image formed on a sheet and then forms a new image on the same sheet, in order to reuse sheets, save paper resources and thus realize environment protection. For example, JP-A-10-88046 discloses a printer that includes an image forming unit using a decolorable ink and a decolorizing unit which decolorizes an image formed by the image forming unit, within the single apparatus. Moreover, as an image forming apparatus, there is an apparatus including an image forming function to form an image with a decolorable image forming material and an image forming function to form an image with a non-decolorable image forming material, within the single apparatus, in order to realize multiple functions. For example, JP-A-6-95494 discloses an image forming apparatus including a developing device which performs development with an ordinary toner and a developing device which performs development with an optically decolorable toner, within the same apparatus.
However, when an electrographic image forming function to heat and fix a toner image formed on a sheet by a fixing device and an ink jet image forming function using a decolorable ink that is thermally decolorable are provided within the same apparatus, it is necessary to prevent the decolorable ink from being affected by heat. As the sheet carrying path is divided between the electrographic system and the ink jet system in order to detour a sheet used in the ink jet system so that the sheet does not pass through the fixing device, the carrying path becomes complex and may obstruct miniaturization.
Thus, it is desired that an image forming apparatus should be developed which has plural image forming functions within the same apparatus and in which an image formed with a decolorable image forming material is prevented from being affected by heat and the sheet carrying path can be simplified.